Gov. Linda Lingle's ambitious goal of achieving energy independence for Hawaii has focused on solar, wind and biofuel alternatives to replace much of the oil now relied upon for the state's electricity. Virtually unnoticed has been a recent partnership to derive energy from differences in ocean water temperatures, but it could play a key role in freeing Hawaii and other parts of the United States from dependency on foreign oil.

The project fits into Lingle's Hawaii Clean Energy Initiative, a partnership launched a year ago with the U.S. Department of Energy, and should put Hawaii in lockstep with the Obama administration's energy policies. Nowhere else in the country does a Republican governor hold joint news conferences with environmental advocates without blinking.

Lingle announced in November that an agreement had been approved with Lockheed Martin Corp. and the Taiwan Industrial Technology Research Institute to develop a 10-megawatt pilot plant to use the difference in temperature between the ocean's warm surface and its colder depths to generate electricity. The method has been at the laboratory stage.

Taiwan and Hawaii “;share very similar challenges of overdependence on imported petroleum for their energy needs,”; Lingle said in announcing the partnership. Hawaii relies on expensive oil for 94 percent of its primary energy while Taiwan is even more dependent on imported oil. Experts say the ocean energy also would be applicable in Puerto Rico, Guam and, in the Indian Ocean, Diego Garcia, where the Navy is conducting similar research.

“;The vagaries of petroleum impact Hawaii far more than any other state,”; Theodore Peck, an energy administrator of the state Department of Business, Economic Development and Tourism, told The New York Times recently. The technology is “;a natural for Hawaii.”;

Under the methodology, which Lockheed is pursuing with Kailua-based Makai Ocean Engineering, Inc., water on the ocean's surface is used to heat a pressurized liquid, usually ammonia, which boils at a temperature slightly cooler than warm seawater.

The resulting gas powers a turbine generator, cold water is pumped from ocean depths through a pipe to condense the gas back to a liquid, and the cycle is repeated. Lockheed is developing a cold-water pipe to be 13 feet in diameter and 40 feet long in its California laboratory. It hopes to obtain financing from the Pentagon and the U.S. Energy Department, as well as the private sector.

A historical footnote: Early research was conducted by Lockheed and the federal government at the Natural Energy Laboratory of Hawaii Authority at Keahole Point, Kona, and a 50-kilowatt test plant to generate the electricity was briefly deployed in the waters off the Big Island in 1979.